DOCSLIB.ORG

Recurrence Frequency of Flood Levels in the Tuggerah Lake System

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Recurrence Frequency of Flood Levels in the Tuggerah Lake System The quality of this digital copy is an accurate reproduction of the original print copy .123 BEOURRENCE FREQUENCY OF FLOOD LEVELS IN THE TUGGERAH LAKE SYSTEM K.C.Yong and P.B.Stone February, 1971 RECURRENCE FREQUENCY OF FLOOD LEVELS IN THE TUGGERAH LAKE SYSTEM by K. C. Yong and P. B. Stone https://doi.org/10.4225/53/57a17218c046d Report No. 123 February, 1971. KEY WORDS Hydrograph analysis Lakes Rainfall Runoff Unit hydrographs 0-85824-009-2 Preface The present study was undertaken by the Water Research Laboratory of the University of New South Wales at the request of the Electricity Commission of New South Wales. Throughout the study close liaison was maintained with the Engineering Staff of the Electricity Commission and the assistance of Messrs. C. G. Coulter and A.N. Lamb is gratefully acknowledged. The study was undertaken by Mr. K. C. Yong, engineer on the staff of the Water Research Laboratory under the supervision of Mr. P.B. Stone and the direction of Mr. D.N.Foster. D,N. Foster, Acting Officer-in-Charge. Summary. This report describes the results of an investigation carried out to estimate the flood levels in Tuggerah, Budgewoi and Munmorah lakes making use of the rainfall-runoff data available over the past seven or eight years, Unitgraphs were derived for Wyong and Ourimbah creeks and syn- thetic unitgraphs computed for Wallarah Creek and the remaining catch- ment areas surrounding the lakes. Inflow hydrographs were computed by applying design rainfalls to the unitgraphso These inflows were routed through the storage system of three lakes, taking into account discharge characteristics of Budgewoi channel, discharge characteristics of constriction at Toukley Bridge and outflow characteristics at the Entrance channel to arrive at the resulting lake levels for floods of various recurrence frequencies. These flood levels can be used to estimate the design basement level for power stations proposed for this area. Table of Contents Page No. Summary 1. Introduction 1. 2o Analysis of Historical Data 1. 3. Catchments 3, 3. 1 Catchment Areas 3. 3. 2 Critical Storm Duration 4. 4. Rainfall 4. 4o 1 Rainfall Data 5. 4. 2 Probable Maximum Precipitation 5, 4.21 Thunderstorm Model 5. 4.22 Transposed U.S.A. Data 6. 4.23 Transposed Dunedoo Storm 6. 4e 3 Summary of Rainfall Results 7. 5. Stream Flows 7. 5. 1 Gauging Stations 7. 5. 2 Unitgraph Derivation 7. 6. Lake and Channel Topography 7. 6. 1 Storage Elevation Relationships 7. 6. 2 Channel Characteristics 8. 7. Model Study of the Entrance Channel 8. 7. 1 Survey Information 8. 7, 2 Scale Ratio 9. 7.21 Linear Ratios 9. 7„ 22 Scour Velocity Ratio 9. 7.23 Friction Ratio 9, 7.24 Scour Time Ratio 10. 7.25 Summary of Scales 10. 7.3 Model Construction 10. 7. 4 Testing Program and Results 11. 8. Inflow Hydrographs 1 8. 1 Temporal Pattern of Storm 1 8,2 Hydrograph Synthesis 1 9. Flood Routing 1 9. 1 Flood Routing Program 1 9. 2 Program Verification 12, 9. 3 Flood Levels 13» Table of Contents (cont'd.) Page No. 10. Storm Surge 16. 11. Conclusions l®* References Appendix I: Seismic Survey - Entrance North Sandspit dated 15th Sept. 1969. Al. Appendix II: Details of the computer programme Bl. List of Figures, Figo 1: Flood stage-recurrence frequency relationship for Tuggerah Lake system. Figo 2: Location of rain gauges and gauging stations for Wyong, Ourimbah and Wallerah catchments. Figo 3: Depth-area-duration curves for Wyong, Ourimbah and Wallerah catchments. Fig. 4: Summary of derived and synthetic 2-hour unitgraphs. Figo 5: The storage elevation relationships for Tuggerah, Budgewoi and Munmorah lakes. Fig. 6: Cross section 'M' at Budgewoi channel. Fig. 7: Cross section at Toukley Bridge. Fig. 8: Contour plan of the Entrance area. Fig. 9: Photograph of the Entrance area. Fig. 10: Cross section C-C at Entrance<, Fig. 11: Particle size distribution curves» Figo 12: The Entrance - lake level and waterway area Fig» 13: The Entrance - Channel water surface width. Figo 14: Temporal storm patterns. Figo 15: Inflow hydrographs for 1 in 10 year return period storm of duration 96 hourSo Figo 16: Inflow hydrographs for 1 in 100 years return period storm of duration 96 hours . Fig. 17: Inflow hydrograph for 1 in 1000 years return period storm of duration 96 hours. Figo 18: Inflow hydrographs for the probable maximum precipitation (P.M. P.) of duration 96 hours. Figo 19: Discharge characteristics of thel^ntrance channel. 1. Introduction This report deals with flood levels in the Tuggerah Lakes system (LakesMunmorah, Budgewoi and Tuggerah). The work was commissioned by the Electricity Commission of New South Wales whose interest in flood levels is related to the design of power stations on the low lying land ad- jacent to the lakes. The information needed was the flood level in the lakes for each of a number of return periods. Two methods were used ; anamlytic rainfall-runoff analysis and an historical analysis of lake levels, 2» Analysis of Historical Data For recent years (1961-1969) records of flood levels were available (Refo4) and prior tothis historical information of reported lake levels has been assembled (Ref, 5), In addition, enquiries were made of the Department of Main Roads who have recently built a road bridge in the area» The data obtained from the various sources are summarised in Table lo Table 1; Summary of Flood Data Year Lake Level Remarks RL.fto 1927 Data taken from Refa 5 (highest reported 1931 101 + 3'-5' / flood level - RLol07o5)o According to 1941 101 + 3'-5' Mr<,Hutton the floods of 1927 and 1949 1946 107.5 J were generally the same heights within one or two inches (Bannister and Hunter's report dated 10, 12, 64). 1949 107o72 This was the highest reported flood level in the boatshed but the flood level taken by Mr. Hutton+ was RL. 107, 28'. Minimum lake level is assumed at RL. 101'» 0 + MroHutton is a local resident who lives adjacent to the northern approaches of the existing wooden bridge. The information given by MroHutton is con- tained in a report submitted by Bannister and Hunter, Land Engineering and Mining Surveyors, to the Division Engineer^ Department of Maiii Roads, Newcastle^ on 10th December 1964« The report was made available by engineers of the Department of Main Roads, Sydney. 2. Table 1 (cont'd. ) Summary of Flood Data Year Lake Level Remarks RL. ft. 1953 101 + 3' -5 Data taken from Ref. 5 1961 102.3 1962 104, 0 1963 105. 2 1964 106.0 Data taken from Ref, 4, 1965 101. 5 1966 101. 8 1967 102.35 1969 102.07 ed There was a slight variation in the maximum report/flood level from the various sources and it was assumed that the maximum level achieved since 1900 was RL. 107. 6. A simplistic analysis of these data leads to the conclusion that the recurrence interval for a lake level of 107. 6 was 70 years. This period may be reduced if a higher level which was not reported occurred in the period. However, it may be said that a crude analysis of the historical data gave a recurrence interval of 70 years for a lake level of RL. 107. 6. From 1S61 to 1969 accurate data of significant lake level rises were available in reference 4. This information was extrapolated using Gambel's theory of extreme value statistics. This theory is expressed in the formula:- -e-b = 1 - 1 where b = (X - X + 0.45 ci ) 0.7797ir the variables being defined as P - the probability of an occurrence of a value equal to or greater than x = 1/tp return period in years e = base of Naperian logarithms b - constant X = average of flood levels in the series standard deviation of the series The extrapolation based on this theory is shown in Figure 1 from which it was deduceflthat the return period for a lake level of RL. 107o 6 is 80 years, comparable with the estimate of 70 years made from the incomplete set of datao The remainder of this report deals with analytic method of predicting lake levels using rainfall-runoff analyses and the results of a mobile bed model study« 3. Catchments 3o 1 Catchment Areas Floods in the lake system are the result of rainfall on the surrounding catchment areas and rainfall on the lakes. Four catchment areas were used in this analysis, namely (i) Wyong Creek upstream of Wyong Weir (134 sq, miles) (ii) Ourimbah Creek (54.45 sq, miles) (iii) Wallarah Creek(i2„.4 sq, miles) (iv) Remaining areas (57,5 sq. miles) The remaining areas were generally small areas adjacent to the lakes and containing no major stream. The drainage patterns to the individual lakes are shown in Table 2. Table 2 Inflow Distribution Lake Lake area Components of Summation Percentage sq® miles drainage areas of areas of total feeding into lake sq, miles sq, miles Tuggerah 22.4 (1) Wyong Creek at Wyong Weir - 134 (2) Ourimbah Ck. 228; 70 88,5 = 54,45 (3) 70 per cent of remaining areas=40,25 Budgewoi 5.5 (1) Wallarah Ck. = 12.4 21o0 8, 1 (2) 15% of remain- ing areas = 8.6 4. Table 2 (cont'd. ) Inflow Distribu" :ion T iike Lake area Componoits of Sunmiation Percentage sq. miles drainage areas of areas of total feeding into lake sq. miles sq. miles Munmorah 3.0 (1) 15% of remain- ing area = 8.6 8. 6 3.4 Total 30.4 Total 258.3 • 1 3. 2 Critical Storm Duration For runoff from the catchments into the lakes the critical storm duration will be short but due to the large storage capacity of the lakes the critical storm duration for lake level will be increased above that for the streams.
Load more

Recommended publications
  • Gosford City Centre Masterplan the Gosford Challenge Gosford City Centre Masterplan
    City, Our destiny Gosford City Centre Masterplan The Gosford ChallenGe Gosford City Centre Masterplan r City, u O destiny a World Class reGional Waterfront City r City, iii u O destiny The Gosford ChallenGe Gosford City Centre Masterplan acknowledgments JOINT PROJeCt SPONSORS DESIGn TEAM Gosford City Council land and property Gosford Challenge team Clr Chris Holstein Management authority Colleen Worthy-Jennings Mayor Hon Tony Kelly MHR Stephen Fairnham Clr Craig Doyle Warwick Watkins Duncan Clarke Deputy Mayor Graham Harding Helen Polkinghorne Clr Chris Burke Brett Phillips John Tilston Clr Peter Freewater Stewart Veitch Barbara Cruise Clr Amy Houston Robert Eyre Clr Terri Latella Scott Burton Clr Jim Macfadyen Steve Green Clr Laurie Maher Sue Verhoek Clr Vicki Scott Kerr Partnering Clr Jeff Strickson Cox Architects and Planners Peter Wilson Patrick Condon Stephen Glen Rob Lane Gary Chestnut Aurecon Rod Williams Arup Nic Pasternatsky Oculus Terry Thirlwell teaming with ideas r City, u O destiny Contents 1 GROWING A REGIONAL CITY 2 4 MAKING IT HAPPEN 92 1.1 gosford as a regional city 3 4.1 implementation plan 93 1.2 greater metropolitan context 4 4.2 the beginning - two priority areas 96 1.3 regional context 5 APPENDICES 1.4 local context 6 appendix 1 sustainability 102 1.5 attributes of a regional city 8 appendix 2 regional benchmarks 110 1.6 purpose of a masterplan 10 appendix 3 retail and commercial market 114 1.7 the journey 12 appendix 4 participants 116 1.8 planning context 14 1.9 key strategic opportunities 15 2 SPATIAL FRAMEWORK 16 2.1 the city framework 16 2.2 the masterplan 18 2.3 five precincts of activity 20 3 MASTERPLAN ELEMENTS 48 3.1 connecting places 50 3.2 activate the city 56 3.3 responsive built form 60 3.4 generate jobs and new enterprises 64 3.5 living in the city 72 3.6 access and movement 76 3.7 sustaining the city (enhancing the natural environment) 86 note: diagrams of future development are concept only.
    [Show full text]
  • Environment and Communications Legislation Committee Answers to Questions on Notice Environment Portfolio
    Senate Standing Committee on Environment and Communications Legislation Committee Answers to questions on notice Environment portfolio Question No: 3 Hearing: Additional Estimates Outcome: Outcome 1 Programme: Biodiversity Conservation Division (BCD) Topic: Threatened Species Commissioner Hansard Page: N/A Question Date: 24 February 2016 Question Type: Written Senator Waters asked: The department has noted that more than $131 million has been committed to projects in support of threatened species – identifying 273 Green Army Projects, 88 20 Million Trees projects, 92 Landcare Grants (http://www.environment.gov.au/system/files/resources/3be28db4-0b66-4aef-9991- 2a2f83d4ab22/files/tsc-report-dec2015.pdf) 1. Can the department provide an itemised list of these projects, including title, location, description and amount funded? Answer: Please refer to below table for itemised lists of projects addressing threatened species outcomes, including title, location, description and amount funded. INFORMATION ON PROJECTS WITH THREATENED SPECIES OUTCOMES The following projects were identified by the funding applicant as having threatened species outcomes and were assessed against the criteria for the respective programme round. Funding is for a broad range of activities, not only threatened species conservation activities. Figures provided for the Green Army are approximate and are calculated on the 2015-16 indexed figure of $176,732. Some of the funding is provided in partnership with State & Territory Governments. Additional projects may be approved under the Natinoal Environmental Science programme and the Nest to Ocean turtle Protection Programme up to the value of the programme allocation These project lists reflect projects and funding originally approved. Not all projects will proceed to completion.
    [Show full text]
  • Challenges of Saltmarsh Rehabilitation in a Non-Tidal Estuary – Perspectives on Delivery of On-Ground Works
    CHALLENGES OF SALTMARSH REHABILITATION IN A NON-TIDAL ESTUARY – PERSPECTIVES ON DELIVERY OF ON-GROUND WORKS M Barnett, N Dixon, A Halcrow, S Tsaprounis, D Ryan Wyong Shire Council, Wyong NSW Background Saltmarshes are a unique component of coastal estuaries in Australia that exist at the land and water interface. Conditions in these areas are highly dynamic and biota must be adapted and specialised to cope with varying degrees of salinity, tidal inundation, competition and disturbance. Their unique position allows saltmarshes to function in several ways including flood and erosion control, storm surge buffering, water quality improvement and seagrass wrack assimilation. For these and many other reasons, not the least being biodiversity, saltmarshes need to be conserved as vital parts of the Australian coastline. Saltmarshes are a diminishing habitat in the coastal biosphere of Australia. New South Wales in particular has the least amount of coastal saltmarsh remaining of any state. Saltmarsh occurs along the entire coastline of NSW, but is generally limited to small patches that have been highly modified. In recognition of the decline and uniqueness of saltmarsh in NSW, it has been listed as an Endangered Ecological Community in NSW under the Threatened Species Conservation Act. On the local scale, it is believed that approximately 85% of the saltmarshes around Tuggerah Lakes have been destroyed, degraded or fragmented since European settlement. Saltmarsh recovery on rehabilitated sites can occur naturally, be assisted through active planting and/or bush regeneration or a combination of both. Natural recovery of saltmarsh communities occurs after disturbance via establishment of seedlings or vegetative expansion of remaining plants.
    [Show full text]
  • Central Coast and Hawkesbury River Recreational Fishing Guide
    Central Coast and Hawkesbury River Recreational Fishing Guide Fisheries Compliance Unit • fish aggregating devices (FADs) to enhance fishing for dolphinfish and even tuna and August 2020 marlin; Fishing is a fun, outdoor activity for the whole • creation of recreational fishing havens; family. Fishing rules help ensure healthy and sustainable fisheries for future generations. • angler facilities such as fish cleaning tables and fishing platforms; The Central Coast’s waterways provide excellent beach, rock, and boat fishing opportunities. This • stocking of freshwater fish in dams and rivers; guide provides essential information on fishing, • essential research on popular recreational fish including any closures and restrictions, which apply species; within the Central Coast district, extending from Munmorah State Recreation Park in the north, to • restoring important fish habitat; the southern bank of the Hawkesbury River. • marine stocking of prawns in estuaries; DPI fisheries officers routinely patrol waterways, • angler education and advisory programs such boat ramps and foreshores to advise anglers about as the Fishcare Volunteer program, fishing responsible fishing practices and to ensure workshops, Get Hooked…it's fun to fish compliance with NSW fishing regulations. primary schools education and fishing guides. Information on bag and size limits and legal fishing Much more information is available at gear can be obtained at www.dpi.nsw.gov.au/fisheries. www.dpi.nsw.gov.au/fisheries or by visiting your local DPI fisheries office. You can pay the NSW recreational fishing fee at www.onegov.nsw.gov.au or by calling 1300 369 To report suspected illegal fishing activity, call the 365 or at many outlets throughout NSW, such as Fishers Watch phone line on 1800 043 536 (free fishing tackle stores, caravan parks, local shops, call) or report on-line at service stations and many Kmart stores.
    [Show full text]
  • The Corridor's Strengths
    The Corridor’s strengths Wyong – a Town Centre with “good bones” Wyong Town Centre has many elements of a great regional centre, including an established fine grain street network with connections to a train station, Wyong River and open spaces. Home to the landmark Art House cultural facility, Council chambers and government agencies, Wyong is the cultural and civic Wyong River – a natural centrepiece core of the corridor. The character of Wyong Town Wyong River flows through the heart of the corridor, presenting as Centre is strengthened by a distinct heritage presence a natural centrepiece. Although access is constrained in some areas, and fine grain built form that line the high streets. the River is a significant asset, supporting an array of recreational activities including kayaking and fishing, as well as walking and cycle along the active transport links by the river foreshore. The River provides an important natural outlook for the surrounding urban Alison Street, Wyong areas. Tuggerah Lake, State Conservation Area (image: itsonlymylife163. blogspot) Natural Assets of Environmental Value The corridor is endowed with natural bushland precincts that provide environmental amenity to residents, workers and visitors. Tuggerah Nature Reserve features predominately untouched Wyong River from the Wyong Milk Factory bushlands and wetlands that have high conservation value, while the nearby Tuggerah State Conservation Area supports sustainable visitation and bushwalking. 26 DRAFT Tuggerah to Wyong Corridor Strategy Great local food, drink, arts and craft The Corridor features a growing number of exciting food, beverage, arts and craft offerings, building on growing interest in local and boutique products. There is a combination of restaurants, cafés, markets, function spaces and specialty stores in the area.
    [Show full text]
  • Learning from the Past Research Project – Central Coast, NSW
    Governance 21 Learning from the Past Research Project – Central Coast, NSW Rolf Fenner Australian Local Government Association Email: [email protected] ABSTRACT In 2003, the then Sustainable Ecosystems Division of the CSIRO was engaged by the Central Coast Region of NSW to undertake a detailed regional futures analysis based on a dynamic systems approach (Senge, 1992). A key component of such a research approach was the need to better understand and appreciate the historical context of previous regional planning policy initiatives. As a regional planning practitioner of several years experience, I was engaged by the CSIRO to undertake this “learning from the past” investigation. This paper summaries the value of such a research project by both examining the methodology adopted and findings arising from such an investigation. In short, the paper argues that as a consequence of reflecting on past policy experiences it is possible to better understand and appreciate what policy decisions were previously undertaken, and subsequently improve the opportunities for future policy decision making and implementation. A total of eighteen individuals were interviewed for the project. The regional participants chosen to be interviewed were a mixture of previous community leaders, politicians or senior professional bureaucrats. To encourage frank discussion and minimise any possibility of conflict of interests, all research participants at the time of interview were no longer in their substantive positions they once held. The process of identifying key individuals and relying on oral histories is not without methodological deficiencies. Whilst acknowledging these potential weaknesses, the project nevertheless was able to make a valuable contribution to regional planning on the Central Coast by identifying previous experiences and policy relationships as they related to matters of social, economic, environmental and local/ regional governance.
    [Show full text]
  • Entrance Dynamics and Beach Condition at the Entrance and North Entrance Beaches
    Wyong Shire Council Entrance Dynamics and Beach Condition at The Entrance and North Entrance Beaches April 2011 Entrance Dynamics and Beach Condition at The Entrance and North Entrance Beaches Prepared by Umwelt (Australia) Pty Limited on behalf of Wyong Council Project Director: Pam Dean-Jones Project Manager: Pam Dean-Jones Report No. 1869/RO5/Final Date: APRIL 2011 2/20 The Boulevarde PO Box 838 Toronto NSW 2283 Ph: 02 4950 5322 Fax: 02 4950 5737 Email: [email protected] Website: www.umwelt.com.au Entrance Dynamics Executive Summary Executive Summary This study was commissioned to provide further analysis of the sediment transport processes affecting sediment budget and coastal morphology at North Entrance Beach and The Entrance to Tuggerah Lake. The aim of the study was to clarify sediment transport linkages between The Entrance channel and North Entrance Beach and to identify and evaluate potential options for managing sedimentary processes in this dynamic coastal landscape, to reduce risks associated with coastal erosion hazards. North Entrance Beach lies at the southern end of the zeta curved Tuggerah coastal embayment. The southern extension of the beach is an intermittent spit and berm which forms at the mouth of the Tuggerah lake entrance channel. In historical times the mouth of the estuary closed for periods of up to three years. The sand deposits were scoured out of the entrance area by major flood flows. Since dredging of the outer entrance shoals commenced in 1993, the average channel width has declined compared to the average pre dredging condition. The range of channel conditions has also narrowed.
    [Show full text]
  • The Entrance Morphodynamic Modelling Prepared for NSW Office of Environment and Heritage
    Tuggerah Lakes– The Entrance Morphodynamic Modelling Prepared for NSW Office of Environment and Heritage Tuggerah Lakes – The Entrance Morphodynamic Modelling Prepared for NSW Office of Environment and Heritage Cardno (NSW/ACT) Pty Ltd ABN 95 001 145 035 Level 9 The Forum 203 Pacific Highway St Leonards NSW 2065 Australia Telephone: 02 9496 7700 Facsimile: 02 9439 5170 International: +61 2 9496 7700 [email protected] www.cardno.com.au © State of NSW and Office of Environment and Heritage November 2013 This document is produced by Cardno solely for the benefit and use by the client in accordance with the terms of the engagement. Cardno does not and shall not assume any responsibility or liability whatsoever to any third party arising out of any use or reliance by any third party on the content of this document. Tuggerah Lakes – The Entrance Morphodynamic Modelling Prepared for NSW Office of Environment and Heritage EXECUTIVE SUMMARY The Tuggerah Lakes system consists of three inter-connected shallow coastal lakes (Tuggerah, Budgewoi and Munmorah) that have a weak and intermittent connection to the ocean at The Entrance. The lakes have a history of water quality issues with development of their catchments leading to increased nutrient, and to a lesser extent sediment, loads. The lakes’ entrance is currently managed through regular dredging by Wyong Council to ensure that the entrance does not close and to achieve objectives related to flooding, water quality in the lower entrance channels and recreational amenity. The dredging does not affect the general water quality in the lakes. Previous assessments have considered the possibility of constructing a training wall or training walls at the entrance to Tuggerah Lakes with the objective of maintaining a permanent entrance to the lakes and thus improving water flows and water quality.
    [Show full text]
  • Settlement of the Tuggerah Lakes
    Settlement of the Tuggerah Lakes The ecological history of the Tuggerah Lakes over the last 200 years is closely linked to the pattern of European settlement both around the lakes and within the upper catchment. As settlement spread throughout the district, activities such as the clearing of land, logging, fishing and urban development have all had impacts on the ecology of the lakes. To understand when each of these impacts occurred, the settlement of the Tuggerah Lakes and its catchment has been divided into four broad time periods. These are; • Aboriginal settlement • The first European settlers (1820s – 1870s) • Settlement after the opening of the railway (1880s – 1950s) • Urban Development (1960s – 1990s) Historical documents which provide an insight into the rates of settlement and associated activities during each of these time periods, are presented in the following sections. Table 1 provides a summary of some key dates in the development of the region. Table 1. Significant events in the development of the Tuggerah Lakes and its catchment Date Activity 1825 First settlers arrived. Early 1830s Logging commenced in the upper catchment, principally for cedar. Early 1830s Felton Mathews surveyed the district. 1832 The Great North Road was opened, principally as a means of providing access to the Hunter District from Sydney. There were two branches from this road into Wyong. 1830s Cabbage Tree Harbour provided a shipping point for cedar from the 1830s onwards. Gosford was another such departure point. Early1850s Hargraves residence at Noraville constructed using cedar from the valleys behind Wyong. 1854 Jane Taylor acquired all the land of what is now The Entrance.
    [Show full text]
  • Recreational Crab Fishing in the Central Coast District
    Recreational Crab Fishing in the Central Coast District Fisheries Compliance Unit claws used for crushing and cutting prey. The two hind legs are flattened for swimming. Mud Crabs July 2021 are generally very dark brown to mottled green in colour. Juveniles feed on planktonic animals, Overview benthic molluscs and crustaceans while adults Crab fishing is a popular recreational fishery and feed on bivalve and gastropod molluscs (mussels important commercial fishery in NSW. and pipis), small crabs and polychaete worms. This fishing guide is designed to provide key information to help: Mud Crab • ensure these fisheries remain sustainable by maximising voluntary compliance with crab fishing rules • reduce conflict between/within user groups • answer commonly asked questions about crab fishing rules • report illegal crab fishing and crab fishing gear theft, and • reduce bycatch and other impacts Popular crab species in NSW There a several popular eating crab species with the main two sought after being the Mud Crab and Blue Swimmer Crab Portunus pelagicus Blue Swimmer Crab. There are many other crab Distribution - Blue swimmer crabs are found in species are found in NSW including the Red Shore coastal waters from Cape Naturaliste in Western Crab, Swift Footed Crab and Soldier Crab which Australia, around the top end to NSW. The are popular bait species. Victorian border is the southern limit for distribution of the species on the east coast. Mud Crab Scylla serrata Distribution - Mud Crab inhabit tropical to warm Size - Maximum length of about 21cm across the temperate waters from Exmouth in Western carapace (shell), and a weight of up to 1kg.
    [Show full text]
  • Measuring Success of Active Saltmarsh Restoration in Tuggerah Lakes
    MEASURING SUCCESS OF ACTIVE SALTMARSH RESTORATION IN TUGGERAH LAKES P Laegdsgaard 1, N McGaharan 2 1Umwelt, Australia, Teralba, NSW 2Wyong Shire Council, Wyong, NSW Abstract As part of the Tuggerah Lakes Estuary Management Plan, Wyong Council identified specific areas for re-establishment of saltmarsh to the shores of the Tuggerah Lakes Estuary. These locations were highly modified and elevated above the water level of the lake. In Tuggerah Lakes the minimal tidal exchange combined with other impacts such as mowing and trampling inhibit the expansion any saltmarsh present. Restoration activities at these sites consisted of excavation to re-grade the foreshore area to reclaim natural hydrological processes suitable for saltmarsh establishment. This was followed by a replanting program using tube-stock and transplantation of salvaged saltmarsh species. It was considered important to establish the success of the restoration activities through a scientifically rigorous monitoring program and an adaptive management approach to the staggered restoration timeframe. It was initially predicted that, with regular watering of newly established saltmarsh with saline/brackish water, recovery could be achieved within 12 to 24 months of planting. Monitoring results showed this was not achieved due to low survivorship of tubestock in the low shore and slow expansion of saltmarsh in the upper shore. This has been linked to lack of regular tidal influence and fluctuating lake levels limiting the rapid expansion of the newly established saltmarsh in the Tuggerah Lakes estuary. It is now evident that rehabilitation to a level of reference sites has been achieved in sites that have had three and a half years of recovery time.
    [Show full text]
  • Investment Prospectus 2018!19 Newcastle
    SYDNEY’S CENTRAL COAST INVESTMENT PROSPECTUS 2018!19 NEWCASTLE AUSTRALIA C E N T R A L COAST 1 H O U R F R O M SYDNEY Contents 1 Sydney’s Central Coast – A Snapshot 5 About the Central Coast 5 A Message from the Parliamentary Secretary for the Central Coast GOSFORD 7 Investment activity 15 Central Coast Regional Plan 2036 17 Gosford City Centre Revitalisation 19 Economic profile 20 Map – Central Coast 22 Key industries 25 Business centres 33 Industrial areas 35 Access to markets – Logistics 36 Infrastructure and utilities 37 Workforce 38 Education and training SYDNEY 39 Lifestyle 44 Who to talk to 44 Acknowledgments Sydney’s Central Coast – A Snapshot 1 Sydney’s Central Coast is a region just over an hour north of Sydney CBD. It is connected to the city by rail, the M1 Pacific Motorway and the soon to be completed North Connex connecting the area with Western Sydney. It forms part of the Sydney Greater Metropolitan Area which has a population of some 3.5 million people. The local working population is 104,734 of which approximately 30% commute into the City each day for work. Most of these commuters would prefer to work locally. The Central Coast has a resident population of 337,000 people and will grow to over 400,000 in the next 25 years. Gosford is the Capital City of the Central Coast and is presently seeing unprecedented investment. The NSW Government has made a commitment to the growth of the region and is investing almost a billion dollars in support of that growth while at the same time private investors have invested a similar amount with plans to spend more.
    [Show full text]